I would never choose the PRO2 again. Especially not for the 80-400. I wouldn't even use a tripod with that lens to be honest but that is me since I also use my 200-400/4 VR without one. But I own a PRO2 and I regret it since I bought it. Way too heavy, too bulky etc. Only usefull when standig in the field for hours, waiting for an animal or next to a sportsfield or anything. Not for carrying it around... I hate it to be honest.

I like the Jobu Pro2, we use it on the GT5542LS for the 600mm f/4.0. I'm surprised you find it bulky and heavy, considering you're shooting the 200-400 f/4.0 hand-held!